The production of drills, for example full-carbide drills, or else the production of drill tips for modular drilling tools, in which the drill tips can be inserted as reversibly exchangeable drill tips into a carrier shank, is usually carried out in several grinding steps, starting from a round blank which is ground to a cylindrical nominal dimension and into which, moreover, spirally coiled chucking grooves are often ground.
In many applications, for improved guidance of the drill in a drillhole made, at least one supporting chamfer is arranged on the drill ridge. Conventionally, after a secondary cutting edge running along the chucking groove, a first supporting chamfer is formed, and a further supporting chamfer is formed at a distance from the latter, for example at the rear end of the drill ridge. A twist drill having, for example, three supporting chamfers can be gathered, for example, from US 465,392 A. In order to generate the supporting chamfers, the drill ridge is ground in a separate grinding step, so that the supporting chamfers are left standing.
In particular in modular drilling tools, this is highly complicated because of the very short axial length of the reversibly exchangeable drill tip which often lies only in the range of once to twice the drill nominal diameter.